Prep the chicken. Pat the chicken breasts dry with paper towels. Using a sharp knife, slice a pocket horizontally into the thickest side of each breast, stopping about 1/2 inch from the opposite side so you don’t cut through. Season the outside with salt, pepper, Italian seasoning, and paprika.

Sauté the spinach. Warm 1 teaspoon of olive oil in a skillet over medium heat. Add garlic and cook until fragrant, about 30 seconds. Add spinach and a pinch of salt. Cook, stirring, until wilted (or warmed through if using thawed spinach), then transfer to a bowl. Let it cool slightly and squeeze out any excess moisture.

Make the filling. In a mixing bowl, combine cream cheese, mozzarella, Parmesan, lemon juice, red pepper flakes, and the cooled spinach. Taste and season with salt and pepper. The mixture should be thick, spreadable, and well-seasoned.

Stuff the chicken. Spoon the filling into each chicken breast pocket, dividing it evenly. Don’t overfill to the point it spills out. Secure the opening with toothpicks, weaving them in like small stitches.

Quick sear for flavor. Heat the remaining olive oil in an oven-safe skillet over medium-high heat. Sear the chicken 2–3 minutes per side until lightly browned. This step adds flavor and helps keep moisture inside.

Bake until done. Transfer the skillet to a 400°F (200°C) oven and bake 12–18 minutes, depending on thickness. The chicken is done when the thickest part reaches 165°F (74°C) on an instant-read thermometer and juices run clear.

Rest and serve. Let the chicken rest for 5 minutes. Remove toothpicks. Serve with a squeeze of lemon and your favorite sides like roasted potatoes, green beans, or a simple salad.